Many people claim (and many others question) the existence of ESP -- Extra Sensory Perception. Erin Moriarty of "48 Hours" has gone searching for answers:

In the 1970s, a handsome ex-Israeli army paratrooper popularized extrasensory perception, or ESP. Uri Geller claimed he could bend spoons with his mind, see inside sealed containers, and even read other people's minds.

It was great television. But off-stage, Geller had also caught the eye of the intelligence community.

"This is where it got very interesting because scientists would consider, 'Wait a minute, maybe we can read the minds of other government officials; maybe we can see inside a nuclear facility in Russia,'" said national security reporter Annie Jacobsen. It sounds incredible, but it's true. Relying on now-declassified documents, Jacobsen has written about the U.S. government's decades-long to attempts to use Uri Geller, and others like him, for psychic espionage.

"It's sort of like a highly-classified black program inside of a black program," Jacobsen said. "One, because you don't want the Russians or the Chinese to know what we are doing; and two, because a lot of scientists didn't want their colleagues to know what they were doing, because of the embarrassment factor."

And there had long been reports, said Jacobsen, that the Kremlin was also experimenting with ways to weaponize people with ESP.

"There's a declassified report that talks about the Pentagon's real fear -- citing Uri Geller by name -- that if he was able to bend metal with his mind, he might be able to use his mind to interfere with the delicate electronic systems on a nuclear-tipped ICBM," Jacobsen said.

But Uri Geller's skills turned out to be unreliable, as on his now-infamous appearance on "The Tonight Show" in 1973.

Johnny Carson: "Uri told me, you don't feel, what, strong tonight? Is that…"
Geller: "I don't feel strong. I can't…"
Carson: "Well, I'm not trying to pressure you. I'm really not."

Still, that didn't stop the government experiments. In the 1980s, the Defense Intelligence Agency began "Project Star Gate," which was, according to Dean Radin, a scientist who worked on the program, top secret. "It's actually beyond top secret."

The program employed about a dozen psychics and mediums. Its aim: espionage.